A phase I study of Mirvetuximab Soravtansine and gemcitabine in patients with FRα-positive recurrent ovarian, primary peritoneal, fallopian tube, or endometrial cancer, or triple negative breast cancer

OBJECTIVE

Platinum-resistant epithelial ovarian cancer (EOC), recurrent endometrial cancer (EC), and triple negative breast cancer (TNBC) are difficult to treat after failing standard therapies. This phase I study evaluated mirvetuximab soravtansine (MIRV) and gemcitabine in patients with recurrent FRα-positive EOC, EC, or TNBC to determine the maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D) (primary endpoint).

METHODS

FRα-positive patients with platinum-resistant EOC, EC, or TNBC with ≤4 prior chemotherapy regimens (2 for EC) were enrolled. FRα expression requirement varied among eligible tumors and changed during the study.

RESULTS

Twenty patients were enrolled; 17 were evaluable for DLT. Half the patients received ≥3 prior chemotherapy lines. Most EOC and EC patients (78%) were medium (50-74%) or high(75-100%) FRα expressors. TNBC patients were low (25-49%) FRα expressors. The MTD/RP2D was MIRV 6 mg/kg AIBW D1 and gemcitabine 800 mg/m2 IV, D1 and D8, every 21 days (Dose Level [DL] 3), where 5/7 patients demonstrated a partial response (PR) as their best response, including 2 confirmed ovarian responses whose time-to-progression and duration of response were 7.9/5.4 and 8.0/5.7 months respectively. Most common treatment-related adverse events at MTD were anemia and neutropenia (3/7 each, 43%), diarrhea, hypophosphatemia, thrombocytopenia, and leukopenia (2/7 each, 29%). DLTs were thrombocytopenia (DL1), oral mucositis (DL4) and diarrhea (DL4). Nine of 20 patients (45%; 95% CI: 21.1-68.9%) achieved PR as their best response, with 3/20 patients or 15% (95%CI, 0-32.1%) confirmed PR.

CONCLUSION

MIRV and gemcitabine demonstrate promising activity in platinum resistant EOC at RP2D, but frequent hematologic toxicities.

Integrative review of remote patient monitoring in gynecologic and urologic surgical oncology

Patients with cancer facing complex and invasive urologic and gynecologic cancer surgery often experience symptoms and rapid declines in functional capacity postoperatively. Remote patient monitoring that leverages patient-generated health data is a potential approach to assess and promote postoperative recovery. This integrative review aims to provide an overview of the current literature and research on remote patient monitoring in gynecologic and urologic surgical oncology.

Consensus statement for treatment protocols in pressurized intraperitoneal aerosol chemotherapy (PIPAC)

Objectives

Safe implementation and thorough evaluation of new treatments require prospective data monitoring and standardization of treatments. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a promising alternative for the treatment of patients with peritoneal disease with an increasing number of suggested drug regimens. The aim was to reach expert consensus on current PIPAC treatment protocols and to define the most important research topics.

Methods

The expert panel included the most active PIPAC centers, organizers of PIPAC courses and principal investigators of prospective studies on PIPAC. A comprehensive literature review served as base for a two-day hybrid consensus meeting which was accompanied by a modified three-round Delphi process. Consensus bar was set at 70% for combined (strong and weak) positive or negative votes according to GRADE. Research questions were prioritized from 0 to 10 (highest importance).

Results

Twenty-two out of 26 invited experts completed the entire consensus process. Consensus was reached for 10/10 final questions. The combination of doxorubicin (2.1 mg/m²) and cisplatin (10.5 mg/m²) was endorsed by 20/22 experts (90.9%). 16/22 (72.7%) supported oxaliplatin at 120 with potential reduction to 90 mg/m² (frail patients), and 77.2% suggested PIPAC-Ox in combination with 5-FU. Mitomycin-C and Nab-paclitaxel were favoured as alternative regimens. The most important research questions concerned PIPAC conditions (n=3), standard (n=4) and alternative regimens (n=5) and efficacy of PIPAC treatment (n=2); 8/14 were given a priority of ≥8/10.

Conclusions

The current consensus should help to limit heterogeneity of treatment protocols but underlines the utmost importance of further research.

Characterizing impact of positive lymph node number in endometrial cancer using machine-learning: A better prognostic indicator than FIGO staging?

BACKGROUND

Number of involved lymph nodes (LNs) is a crucial stratification factor in staging of numerous disease sites, but has not been incorporated for endometrial cancer. We evaluated whether number of involved LNs provide improved prognostic value.

PATIENTS AND METHODS

Patients diagnosed with node-positive endometrial adenocarcinoma without distant metastasis were identified in the National Cancer Database. We trained a machine-learning based model of overall survival. Shapley additive explanation values (SHAP) based on the model were used to identify cutoffs of number of LNs involved. Results were validated using a Cox proportional hazards regression model.

RESULTS

We identified 11,381 patients with endometrial cancer meeting the inclusion criteria. Using the SHAP values, we selected the following thresholds: 1-3 LNs, 4-5 LNs, and 6+ LNs. The 3-year OS was 82.0% for 1-3 LNs, 74.3% for 4-5 LNs (hazard ratio [HR] 1.38; p < 0.001), and 59.9% for 6+ LNs (HR 2.23; p < 0.001). On univariate Cox regression, PA nodal involvement was a significant predictor of OS (HR 1.20; p < 0.001) but was not significant on multivariate analysis when number of LNs was included (HR 1.05; p = 0.273). Additionally, we identified an interaction between adjuvant therapy and number of involved LNs. Patients with 1-3 involved LNs had 3-year OS of 85.2%, 78.7% and 74.2% with chemoradiation (CRT), chemotherapy, and radiation, respectively. Patients with 6+ involved LNs had 3-yr OS of 67.8%, 49.6%, and 48.9% with CRT, chemotherapy, and radiation, respectively (p < 0.001).

CONCLUSION

Number of involved LNs is a stronger prognostic and predictive factor compared to PA node involvement.

Abstract 2432: Somatic mutations in the STAT3 activation pathway are associated with improved survival in gynecologic malignancies and provide a molecular rationale for therapeutic targeting

Background: Signal transducer and activator of transcription 3 (STAT3) activation promotes tumor cell survival, immune evasion, metastasis, and drug resistance in PARP inhibitors and platinum-based chemotherapy.

Objective: Based on our in-vitro findings of the tumoricidal potential of STAT3 inhibition in BRCAwild-type and PARP inhibitor-resistant tumor cells, we sought to evaluate whether ovarian and uterine cancer patients with somatic mutations in the STAT3 activation pathway had improved overall survival (OS) compared to those with intact STAT3 activation pathway-related genes.

Method: We induced Olaparib resistance in BRCAwild-type ovarian cancer cell lines (OVCAR8 and A2780) and treated both parental and PARP inhibitor-resistant cell lines with various STAT3 inhibitors. We then attempted to establish clinical correlations of our in-vitro studies and queried the Cancer Genome Atlas (TCGA) Pan-Cancer Atlas for uterine and ovarian cancers. OS in patients with somatic mutations in the STAT3 gene and/or associated STAT3 activation genes (IL6ST, GNAS, JAK1, JAK2) was compared to OS in patients with intact STAT3 pathway-related genes. Kaplan-Meier survival curves were compared using the log-rank test.

Results: In-vitro, STAT3 inhibition demonstrated potent, tumoricidal propensity in all cell lines (EC50: 0.34uM-0.46uM) including A2780parental, A2780parpi-resistant, OVCAR8parental, and OVCAR8parpi-resistant. Clinically, 1,154 total patients were identified in TCGA, including 571 high-grade serous ovarian carcinoma, 397 uterine endometrioid adenocarcinomas, 109 uterine serous carcinoma/uterine papillary serous carcinomas, 56 uterine carcinosarcomas/uterine malignant mixed Mullerian tumors, and 21 uterine mixed endometrial carcinomas. When pooling all uterine and ovarian cancer patients, median survival (MS) was 52 months (0-185) in patients with intact STAT3 (n=1,007) compared to not reached (NR, 0-225) in the STAT3 mutated group (n=147) with a Hazard Ratio (HR) of 0.25 and Confidence Interval (CI) 0.20-0.32 (p&lt;0.001). In ovarian cancer patients, MS was 45 months (0-180) in patients with intact STAT3 (n=551) compared to 95 months (0-145) in the STAT3 mutated group (n=20) with a HR of 0.48 and CI 0.29-0.80 (p=0.038). In uterine cancer patients, MS was 112 months (0-185) in patients with intact STAT3 (n=456) compared to NR (0-225) in the STAT3 mutated group (n=127) with a HR of 0.40 and CI 0.25-0.64 (p=0.003).

Conclusion: Pharmacologic and genetic (siRNA) inhibition of the STAT3 activation pathway killed PARP inhibitor-resistant ovarian cancer cells in-vitro. Clinically, somatic mutations in the STAT3 activation pathway were associated with improved OS in both ovarian and uterine cancer. These findings provide a rationale for the therapeutic targeting of this pathway in gynecologic malignancies.

Citation Format: Adrian Kohut, Antons Martincuks, Thanh Dellinger, Hua Yu, Lorna Rodriguez-Rodriguez. Somatic mutations in the STAT3 activation pathway are associated with improved survival in gynecologic malignancies and provide a molecular rationale for therapeutic targeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2432.

Allogeneic human neural stem cells for improved therapeutic delivery to peritoneal ovarian cancer

BACKGROUND

Immortalized, clonal HB1.F3.CD 21 human neural stem/progenitor cells (NSCs), loaded with therapeutic cargo prior to intraperitoneal (IP) injection, have been shown to improve the delivery and efficacy of therapeutic agents in pre-clinical models of stage III ovarian cancer. In previous studies, the distribution and efficacy of the NSC-delivered cargo has been examined; however, the fate of the NSCs has not yet been explored.

METHODS

To monitor NSC tropism, we used an unconventional method of quantifying endocytosed gold nanorods to overcome the weaknesses of existing cell-tracking technologies.

RESULTS

Here, we report efficient tumor tropism of HB1.F3.CD 21 NSCs, showing that they primarily distribute to the tumor stroma surrounding individual tumor foci within 3 h after injection, reaching up to 95% of IP metastases without localizing to healthy tissue. Furthermore, we demonstrate that these NSCs are non-tumorigenic and non-immunogenic within the peritoneal setting.

CONCLUSIONS

Their efficient tropism, combined with their promising clinical safety features and potential for cost-effective scale-up, positions this NSC line as a practical, off-the-shelf platform to improve the delivery of a myriad of peritoneal cancer therapeutics.

Silica Coated Paclitaxel Nanocrystals Enable Neural Stem Cell Loading For Treatment of Ovarian Cancer

Ovarian cancer is commonly diagnosed only after it has metastasized to the abdominal cavity (stage III). While the current standard of care of intraperitoneal (IP) administration of cisplatin and paclitaxel (PTX) combination chemotherapy has benefit, patient 5-year survival rates are low and have not significantly improved in the past decade. The ability to target chemotherapy selectively to ovarian tumors while sparing normal tissue would improve efficacy and decrease toxicities. We have previously shown that cisplatin-loaded nanoparticles (NPs) loaded within neural stem cells (NSCs) are selectively delivered to ovarian tumors in the abdominal cavity following IP injection, with no evidence of localization to normal tissue. Here we extended the capabilities of this system to also include PTX delivery. NPs that will be loaded into NSCs must contain a high amount of drug by weight but constrain the release of the drug such that the NSCs are viable after loading and can successfully migrate to tumors. We developed silica coated PTX nanocrystals (Si[PTX-NC]) meeting these requirements. Si[PTX-NC] were more effective than uncoated PTX-NC or Abraxane for loading NSCs with PTX. NSCs loaded with Si[PTX-NC] maintained their migratory ability and, for low dose PTX, were more effective than free PTX-NC or Si[PTX-NC] at killing ovarian tumors in vivo. This work demonstrates that NSC/NP delivery is a platform technology amenable to delivering different therapeutics and enables the pursuit of NSC/NP targeted delivery of the entire preferred chemotherapy regimen for ovarian cancer. It also describes efficient silica coating chemistry for PTX nanocrystals that may have applications beyond our focus on NSC transport.

Abstract 2024: Hyaluronic acid conjugated nanoparticle delivery of siTWIST reduces tumor burden and enhances chemosensitivity in ovarian cancer

Purpose: TWIST is a transcription factor critical to embryonic development, and aberrantly activated in many cancers. It regulates epithelial-to-mesenchymal transition (EMT), the process underlying metastatic spread and drug resistance. The majority of epithelial ovarian cancer (EOC) patients respond well to chemotherapy, but relapse with metastatic and drug-resistant disease. We are investigating the role of TWIST-mediated relapse, with the goal of developing treatments that sensitize chemoresistant tumors and improve survival.

Experimental Procedures: We employ siRNA to target TWIST mRNA and have created a mesoporous silica nanoparticle with hyaluronic acid (siTWIST-MSN-HA) as a delivery vehicle. Microscopy was conducted to ensure cancer stem cell (CSC) targeting via CD44, and efficient uptake of MSN-HAs. We tested TWIST knockdown combined with cisplatin in vitro and in vivo. At necropsy, total tumor, metastasis, and ascites were evaluated to determine effects of siTWIST-MSN-HA compared to cisplatin alone. qPCR was conducted on tumors to examine effect of siRNA against TWIST, and its target genes. Mice were imaged via bioluminescence to observe CSC localization of siTWIST-MSN-HA compared to siTWIST-MSN (No HA). Tissue sections were stained via IHC to determine MSN-HA tumor targeting. CD44 staining was conducted to reveal HA co-localization in tumor.

Results: siTWIST-MSN-HAs significantly knocked down TWIST, and sensitized cells to cisplatin compared to control in vitro. Following necropsy, tumor quantification revealed mice treated with siTWIST-MSN-HAs plus cisplatin exhibited a startling 75% loss of overall tumor burden (p=0.0012), 88% loss of total metastasis (p=0.001), and further 86% loss of total ascites (p=0.002) compared to cisplatin-alone treatment groups.

EMT target expression by qPCR analysis revealed loss of TWIST1, vimentin, N-cadherin, and gain of E-cadherin in tumors treated with siTWIST-MSN-HA compared to controls. Bioluminescent images of mice at necropsy revealed highly specific tumor localization of MSN-HA Dylight (680nm) compared to MSN without HA. MSN-HA exhibited CSC targeting at metastatic sites, where most of the signal was emitted from the primary tumor; and negligible quantities of MSN-HAs were detected elsewhere. MSN-HA RITC (576nm) reveals highly specific tumor targeting via IHC; MSN-HA nanoparticles localized primarily in tumor cells and not in control organs. CD44 staining of these tissues reveals MSN-HAs co-localized with CD44 in CSCs.

Conclusions: These studies demonstrate TWIST as a promising target for metastasis and acquired drug resistance in EOC. MSN-HAs provide CSC specific CD44 targeting with high efficacy and reduce tumor burden via siTWIST therapy. Thus, siTWIST-MSN-HAs provide a promising platform to improve survival from metastatic, drug-resistant ovarian cancer.

Citation Format: Carlotta A. Glackin, Sophia A. Shahin, Shirleen Simargi, Ruining Wang, Altagracia Contreras, Liliana Parra, Loiuse Qu, Wei Wen, Thanh Dellinger, Julia Unternaehrer, Fuyujiko Tamanoi, Jeffrey Zink. Hyaluronic acid conjugated nanoparticle delivery of siTWIST reduces tumor burden and enhances chemosensitivity in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2024.

Abundance and population structure of Plesionika narval (Fabricius, 1787) in the Northeastern Atlantic

Analysis of abundance and population structure of Plesionika narval was performed on data concerning 5,255 specimens obtained from 62 fishing sets carried out off the Madeira archipelago (Northeastern Atlantic) between 2004 and 2008 in a depth range from 101 to 350 m. Abundance ranged from 0.01 to 19.74 specimens-per-trap and significant differences were found between seasons, probably as a result of an increment of population in the spring during the recruitment season. The analysis of size distribution revealed that the carapace length (CL) ranged from 2.45 to 28.61 mm and that mean female size consistently exceeded that of males. Differences in mean CL were statistically significant between depth strata and seasons. Of the specimens sampled, 57.00% were males, 41.88% females and 1.42% undetermined. Sex ratio also differed significantly between seasons according to depth strata, consolidating the hypothesis of the existence of seasonal migrations related with the reproductive cycle of this species. Ovigerous females showed larger sizes and occurred all year around and remain in shallow waters in winter, summer and autumn and move to deeper waters in spring. The highest frequency of ovigerous females was recorded in summer, between 151 and 200 m deep supporting the hypothesis that spawning of this species occurs in shallow waters, especially in late summer.

Hyaluronic acid conjugated nanoparticle delivery of siRNA against TWIST reduces tumor burden and enhances sensitivity to cisplatin in ovarian cancer

TWIST protein is critical to development and is activated in many cancers. TWIST regulates epithelial-mesenchymal transition, and is linked to angiogenesis, metastasis, cancer stem cell phenotype, and drug resistance. The majority of epithelial ovarian cancer (EOC) patients with metastatic disease respond well to first-line chemotherapy but most relapse with disease that is both metastatic and drug resistant, leading to a five-year survival rate under 20%. We are investigating the role of TWIST in mediating these relapses. We demonstrate TWIST-siRNA (siTWIST) and a novel nanoparticle delivery platform to reverse chemoresistance in an EOC model. Hyaluronic-acid conjugated mesoporous silica nanoparticles (MSN-HAs) carried siTWIST into target cells and led to sustained TWIST knockdown in vitro. Mice treated with siTWIST-MSN-HA and cisplatin exhibited specific tumor targeting and reduction of tumor burden. This platform has potential application for overcoming clinical challenges of tumor cell targeting, metastasis and chemoresistance in ovarian and other TWIST overexpressing cancers.

Intraperitoneal Administration of Neural Stem Cell-Nanoparticle Conjugates Targets Chemotherapy to Ovarian Tumors

Ovarian cancer is particularly aggressive once it has metastasized to the abdominal cavity (stage III). Intraperitoneal (IP) as compared to intravenous (IV) administration of chemotherapy improves survival for stage III ovarian cancer, demonstrating that concentrating chemotherapy at tumor sites has therapeutic benefit; unfortunately, IP therapy also increases toxic side effects, thus preventing its completion in many patients. The ability to target chemotherapy selectively to ovarian tumors while sparing normal tissue would improve efficacy and decrease toxicities. We have previously shown that tumor-tropic neural stem cells (NSCs) dramatically improve the intratumoral distribution of nanoparticles (NPs) when given intracerebrally near an orthotopic brain tumor or into a flank xenograft tumor. Here, we show that NPs either conjugated to the surface of NSCs or loaded within the cells are selectively delivered to and distributed within ovarian tumors in the abdominal cavity following IP injection, with no evidence of localization to normal tissue. IP administration is significantly more effective than IV administration, and NPs carried by NSCs show substantially deeper penetration into tumors than free NPs. The NSCs and NPs target and localize to ovarian tumors within 1 h of administration. Pt-loaded silica NPs (SiNP[Pt]) were developed that can be transported in NSCs, and it was found that the NSC delivery of SiNP[Pt] (NSC-SiNP[Pt]) results in higher levels of Pt in tumors as compared to free drug or SiNP[Pt]. To the best of our knowledge, this work represents the first demonstration that cells given IP can target the delivery of drug-loaded NPs.

Prospective study of the fishery of the shrimp Plesionika narval (Fabricius, 1787) in the Northeastern Atlantic

Several experimental surveys were carried out in the Northeastern Atlantic, Madeira archipelago from 1991 to 2008 to explore new fisheries resources. This study examined the selectivity of bottom and floating traps and the analysis of yield-per-recruit (YPR) and biomass-per-recruit (BPR) providing helpful insight to the management of the shrimp Plesionika narval. A total of 28,262 specimens were sampled and the analysis of length at first capture returned higher values when using floating traps indicating that these traps are more selective, exerting less pressure on the resource. The YPR and BPR analysis showed that the stock is under exploited for the studied area and suggests that the use of floating traps in the commercial fisheries of P. narval is recommended, which will allow a higher maximum allowable limit of exploitation and greater yield. The results suggest that P. narval has the potential to support a viable and sustainable fishery using floating traps.

Abstract A42: TWIST1 as a driver of accelerated tumor growth and drug resistance: Potential novel pathways and therapeutics

Introduction: Epithelial ovarian cancer (EOC) is particularly deadly due to its fast rate of growth, dissemination, and chemoresistant recurrences. Novel therapies are urgently needed to limit metastasis and restore platinum sensitivity. We have investigated the role of TWIST1, a basic helix-loop-helix transcription factor, in these processes. TWIST1 is a well-documented regulator of metastasis from solid tumors, which has been linked to cancer stem cell phenotypes, drug resistance, and poor prognosis in several tumor types. Here we present in vitro and in vivo data supporting TWIST1's role in EOC growth and drug resistance, and propose a therapeutic modality to target TWIST1.

Methodology:

In vitro and in vivo studies: We created two cell lines, derived from the EOC line OVCAR8, that differ only in their TWIST1 expression. The cells were stably transfected with a G418-selectible vector containing either TWIST1 or an shRNA targeting TWIST1, under the control of the CMV viral promoter. Cells from each line were injected IP (intraperitoneally) into NSG mice, allowed to grow for 7 weeks, and tumor burden was evaluated at necropsy. In addition, RNA from each of these OVCAR8 cell lines (TWIST1 overexpressing versus knockdown) was isolated and used for RNA-seq analysis. Raw data was processed using the Galaxy online platform, and differentially expressed genes were further analyzed using Ingenuity Pathway Analysis. To determine the effect of TWIST1 on drug resistance, OVCAR8 cells with and without TWIST1 were treated with varying doses of cisplatin, and survival was quantified using colorimetric cytotoxicity assays.

Therapeutic Application: Since we and others have shown that TWIST1's transactivation/protein binding (WR) domain is required for TWIST1 function, we produced a fusion protein comprised of GFP and the WR domain, and used CoIP to evaluate its ability to competitively inhibit TWIST1 binding in HEK 293 cells.

Results: TWIST1 knockdown resulted in reduced tumor size and overall tumor burden in an NSG mouse model of EOC. Specifically, all mice receiving TWIST1-overexpressing cells developed primary ovarian tumors which were scored +4 on H&E by a veterinary pathologist, whereas only 50% of animals with TWIST1 knockdown developed ovarian tumors, and only 1 of 4 mice had a tumor that scored +4. In addition, fewer metastases were present in mice receiving TWIST knockdown cells, and no mice with TWIST1 knockdown tumors produced ascites. RNA-seq analysis of the TWIST overexpressing versus knockdown cell lines revealed marked differences in genes and pathways responsible for cell migration and cell survival, including upregulation of genes implicated in metastasis, DNA repair, and resistance to apoptosis in TWIST1 overexpressing cells. TWIST1 overexpressing cells also showed less cell death following cisplatin treatment. Finally, in our in vitro inhibitor tests, a GFP-WR domain fusion protein successfully reduced TWIST1 binding to its partner protein NFkB-p65 in HEK 293 cells.

Conclusions: The importance of TWIST1 for tumor growth has been demonstrated for multiple tumor types – including ovarian cancer, as presented here. Our RNA-seq analysis reveals a complex network of TWIST1-mediated factors implicated in cell movement, survival, and resistance to DNA damaging agents, and we are working to determine the most important of these pathways in EOC. Most importantly, we have shown that TWIST1 expression in EOC cells leads to greater tumor burden in a mouse model, and by knocking down TWIST1, we were able to prevent peritoneal metastases and reduce tumor size. Therefore, we believe that TWIST1 is an attractive therapeutic target in EOC, owing to its roles at the crossroads of metastasis, drug resistance, and tumor growth.

Citation Format: Cai M. Roberts, Michelle A. Tran, James Finlay, Sophia Allaf Shahin, Joana Loeza, Leslie Cisneros, Emily Ye, Thanh Dellinger, Carlotta A. Glackin. TWIST1 as a driver of accelerated tumor growth and drug resistance: Potential novel pathways and therapeutics. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A42.

Abstract POSTER-THER-1426: Characterization and targeting of TWIST family proteins to prevent chemoresistance and metastasis in ovarian cancer

INTRODUCTION/PURPOSE: The vast majority of epithelial ovarian cancer (EOC) patients present with advanced metastatic disease, but will respond well to first line chemotherapy consisting of a platinum drug and/or paclitaxel. Unfortunately, most of these patients will relapse with disease that is both metastatic and drug resistant, leading to a five-year survival rate under 20%. Therefore, novel therapies that can eliminate disseminated and chemoresistant cells are urgently needed. Two potential targets to supplement current treatment are TWIST1 and TWIST2, related basic helix-loop-helix transcription factors vital in development and reactivated in many cancers. TWIST proteins regulate epithelial to mesenchymal transition (EMT), the process underlying metastatic spread. Furthermore, recent studies from multiple groups have correlated mesenchymal characteristics with a cancer stem cell phenotype, and with chemoresistance to a variety of agents. However, transcription factors are difficult to target with small molecule drugs due to their nuclear localization. Therefore, we employ siRNA to target TWIST mRNA, in order to reduce metastasis and re-sensitize cancer cells to conventional chemotherapeutic agents.

METHODS: We have designed and validated two siRNAs against TWIST. We have also developed two nanoparticle-based delivery systems for siRNA which would be translatable from the bench to the clinic. The first is YTZ3-15, an amphiphilic generation three poly(amidoamine) (PAMAM) dendrimer, the second, a polyethylenimine (PEI) coated mesoporous silica nanoparticle (MSNP). Several EOC cell lines varying in their TWIST1 and TWIST2 expression were treated siRNA delivered via YTZ3-15 or MSNPs. Fluorescent microscopy was used to evaluate siRNA uptake. Western blotting and qRT-PCR were used to assay TWIST knockdown. Sulphorhodamine B and MTT cytotoxicity assays were used to test chemosensitivity before and after TWIST knockdown. TWIST1 levels in clinical samples were evaluated using IHC.

RESULTS: Fluorescent microscopy demonstrated that all tested cell lines efficiently take up PAMAM dendrimers and MSNPs, delivering their siRNA cargo to the cell interior. Tracking of punctate signals over time showed slow release from endosomes into the cytosol. Both YTZ3-15 and MSNP delivery of siRNA resulted in robust TWIST knockdown lasting at least one week post-transfection. Furthermore, TWIST knockdown sensitized cells to chemotherapy compared to cells treated with non-targeting control siRNA. In clinical samples, nuclear TWIST1 staining correlated with tumor stage, with early stage tumors showing cytoplasmic staining, and staining in surrounding cells rather than tumor cells themselves.

CONCLUSIONS: TWIST family proteins are promising targets to address the compound problems of metastasis and acquired drug resistance in EOC. Addition of TWIST inhibitors, such as the siRNA-based technologies we have developed, to a traditional treatment regimen has the potential to cure currently intractable disease. These combined therapies will drastically improve survival and provide new hope for patients with recurrent ovarian cancer.

Citation Format: Cai Roberts, Gina Lowe, James Finlay, Joana Loeza, Thanh Dellinger, Ernest Han, Jeff Zink, Fuyu Tamanoi, Carlotta Glackin. Characterization and targeting of TWIST family proteins to prevent chemoresistance and metastasis in ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1426.

Abstract A41: Harnessing neural stem cell tumor tropism for targeted nanoparticle delivery: Potential for ovarian cancer therapy

Intraperitoneal as compared to intravenous administration of chemotherapy has shown improved survival rates for stage III ovarian cancer. While this demonstrates that concentrating chemotherapy at the tumors has therapeutic benefit, intraperitoneal therapy was also accompanied by significantly increased toxic side effects. There is thus an urgent need for a targeted delivery system that could localize therapy at the tumors and decrease the side-effects. Here we show that stem cell/nanoparticle hybrids may be used for such targeted therapy. In pre-clinical brain and other invasive and metastatic tumor models, neural stem cells have been shown to overcome a variety of biological barriers and migrate selectively to invasive tumor foci, even penetrating hypoxic tumor regions. Here we present data confirming that neural stem cells also migrate selectively to ovarian cancer. Moreover, the neural stem cells can engineered to transport to the tumors nanoparticles that either contain chemotherapy drugs or can be induced to heat. The combination of neural stem cells and nanoparticles that can either be used for thermal ablation or slowly release chemotherapy drugs offers the potential to realize a modular and general drug targeting system for the treatment of stage III ovarian cancer.

Citation Format: Rachael Mooney, Megan Gilchrist, Yiming Weng, Alexander Annala, Sukhada Bhojane, Elizabeth Garcia, Luella Roma, Kenna Schnarr, Thanh Dellinger, Ernest Han, Aboody S. Karen, Jacob M. Berlin. Harnessing neural stem cell tumor tropism for targeted nanoparticle delivery: Potential for ovarian cancer therapy. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A41.

Reliability assessment of soluble c-erbB-2 concentrations in the saliva of healthy women and men

BACKGROUND

The protein c-erb B-2, also known as Her2/neu, is a prognostic breast cancer marker assayed in tissue biopsy specimens from women diagnosed with malignant tumors. Current studies suggest that soluble fragments of the c-erb B-2 oncogene may be released from the cell surface and become detectable in patients with a carcinoma of the breast. Consequently, the purpose of this study is to assay soluble c-erb B-2 protein in the saliva of healthy men and women to determine the reliability of the assay.

METHODS

To determine the diagnostic utility of this oncogene, we assayed the soluble form of the c-erb B-2 protein in the saliva with an enzyme-linked immunosorbent assay. The study population consisted of 10 healthy women and 9 healthy men who were serially sampled for saliva 3 times a day for a 5-day period. Saliva was collected from each subject at 9 AM, 4 PM, and 9 PM during the 5-day period.

RESULTS

We found the presence of c-erb B-2 protein in the saliva of both groups of subjects. The salivary levels of c-erb B-2 were not significantly different when compared for gender differences. Likewise, the results suggest that sampling during various times of the day for salivary c-erb B-2 levels has no effect on marker concentration. Reliability analyses showed that supervised salivary collections were more reliable than unsupervised collections.

CONCLUSIONS

The results of this pilot study suggest that the assay for salivary c-erb B-2 protein is reliable and might have potential use in the initial detection and follow-up screening for the recurrence of breast cancer in both men and women.

The presence of soluble c-erbB-2 in saliva and serum among women with breast carcinoma: a preliminary study

The protein c-erbB-2, also known as Her2/neu, is a prognostic breast cancer marker assayed in tissue biopsies from women diagnosed with malignant tumors. Present studies suggest that soluble fragments of the c-erbB-2 oncogene may be released from the cell surface and become detectable in patients with carcinoma of the breast. Consequently, the purpose of this study was to assay the c-erbB-2 protein in the saliva and serum of women with and without carcinoma of the breast and to determine whether the protein possesses any diagnostic value. To determine the diagnostic utility of this oncogene, the soluble form of the c-erbB-2 protein was assayed in the saliva and serum using ELISA in three different groups of women. The three groups consisted of 57 healthy women, 41 women with benign breast lesions, and 30 women diagnosed with breast cancer. To compare the relative diagnostic utility of the c-erbB-2 protein, CA 15-3 was also measured. The CA 15-3 measurements served as a "gold standard" by which to compare the c-erbB-2 protein's diagnostic effectiveness. We found c-erbB-2 protein in the saliva and serum of all three groups of women. The salivary and serological levels of c-erbB-2 in the cancer patients, however, were significantly higher (P < 0.001) than the salivary and serum levels of healthy controls and benign tumor patients. Additionally, the c-erbB-2 protein was found to be equal to or to surpass the ability of CA 15-3 to detect patients with carcinoma. The results of the pilot study suggest that the c-erbB-2 protein may have potential use in the initial detection and/or follow-up screening for the recurrence of breast cancer in women.

Oral contraceptive usage and the expression of CA 15-3 and c-erbB-2 in the saliva of healthy women

OBJECTIVE

This study was conducted to determine if oral contraceptive use affected the salivary levels of 2 cancer biomarkers, cancer antigen 15-3 (CA 15-3), and c-erbB-2 (erb) among women.

STUDY DESIGN

A total of 40 women were recruited for this study, 20 controls and 20 using oral contraceptives. The average ages were 27.4 years (control) and 27.1 years (using estrogen supplements). Stimulated whole saliva specimens were collected from each woman. CA 15-3 levels were determined using enzyme immunoassay (EIA) while c-erbB-2 levels were determined by standard ELISA methods.

RESULTS

Findings from this study indicate that there were no significant differences between the control and study groups.

CONCLUSIONS

Therefore, saliva may be a useful tool for monitoring women with high estrogen levels due to either tumor load or any treatment regimen, i.e., the levels of the cancer biomarkers CA 15-3 and erb are not affected by increased levels of estrogen in the body.

CA 15-3 and c-erbB-2 presence in the saliva of women

Two markers used to aid in the diagnosis and treatment of breast cancer were examined in the saliva of a cohort of 135 healthy women. The investigators detected the presence of cancer antigen 15-3 (CA 15-3) and c-erbB-2 in the saliva sampled from the 135 women. The marker concentrations for CA 15-3 and c-erbB-2 were also evaluated and compared in terms of tobacco usage, menopausal status, estrogen usage, systemic diseases, prescription medications, race, and age. The results of the study showed no association between the aforementioned variables and salivary marker concentrations. The results of this study establish a baseline for measuring the biomarkers in the saliva of women with no evidence of malignant disease and add further support to the notion that salivary concentrations of CA 15-3 and c-erbB-2 may be useful in the detection of breast cancer and/or the post operative follow-up of patients being treated for carcinoma of the breast.

Estimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?

Analysis of teleost sagittal otoliths contained in scats has been widely used to determine the diet of seals. This method is based on the assumption that relative frequencies of otoliths in scats faithfully reflect those offish in the diet. This assumption has rarely been tested experimentally. We compared the ratios of herring (Clupea harengus) to sprat (Sprattus sprattus) otoliths in faeces (output) of captive California sea lions (Zalophus californianus) and South American fur seals (Arctocephalus australis) with the ratios at feeding (input). Sea lions and fur seals showed no consistent differences in recovery rates and partial digestion of otoliths. Output ratios deviated only slightly from input ratios, the smaller sprat otoliths being underrepresented in the output by 8%. Only about 40% of the otoliths fed to the seals were found in the scats. For both species partial digestion of otoliths led to a 16% underestimation of fish length and a 35% underestimation of fish mass.